1. Field of the Invention
The present invention relates to infiltration measuring device and method for observing, with time, an infiltration of an infiltrative material as fluid into the surface of a target object such as a sheet-like medium including film or coated paper without damaging the target object.
2. Description of the Related Art
There is a printer which generates a functional component as document, image, or electric circuit by attaching a fluid as ink onto a printed material as sheet-like medium. Such a printer evaluates a fluid infiltration into the sheet-like medium along thickness.
The evaluation of the fluid infiltration can be used, for example, for improving image quality, optimizing an amount of applied fluid, and enhancing reliability of a functional component. Japanese Patent Application Publication No. 2005-127938 (Reference 1) discloses cutting a fluid permeated object such as a printed material and observing a cross section of the object with a mass spectrometer or a scanning electron microscope for evaluation, for example.
In Reference 1 the surface of the target object is cut at a certain angle to capture an image of the cut surface and evaluate an infiltrated state of fluid in the target object.
However, there may be a possibility that the target object is damaged or destroyed by cutting. In view of this, the target object is embedded into a resin and frozen before cutting.
Further, Japanese Patent Application Publication No. 2004-333228 (Reference 2), for instance, discloses making a fluid infiltrated in the target object fluorescent with a laser beam, detecting a fluorescence with a co-focal optical system and converting it to a photoelectric detection signal to form an image of the infiltrated fluid along the thickness of the target object. By this technique the infiltrated state of fluid can be measured without cutting the target object.
The technique in Reference 1 is a destructive testing so that it cannot continuously observe a temporal change in the fluid infiltration with time.
Meanwhile, the technique in Reference 2 is a non-destructive testing and able to continuously observe a temporal change in the fluid infiltration with time.
However, this technique needs to detect a feeble fluorescence. If the target object is a paper and an infiltrated fluid is ink, for example, it is not possible to detect a fluorescence from a deep portion of the paper due to a large scattering effect by a paper surface. Thus, only the infiltration near the paper surface is observable.